Hydraulic pump



April 3, 1951 R. F. HCR-rob.

HYDRAULIC PUMP Filed NOV. l5, 1945 5 Sheets-Sheet l ATTORNEY R. F. HORTON HYDRAULIC PUMP pril 3,A 1951 3 Sheets-Sheet 2 Filed Nov. l5, 1945 ATTORN April 3, 1951 R. F. HORTON 2,547,545

HYDRAULIC PUMP Filed Nov. l5, 1945 3 Sheets-Sheet 3 INVENTOR Pofe Mera/v.

'BY @JMW ATTORN EY Patented Apr. 3, 1951 HYDRAULIC PUMP Roger F. Horton, Hempstead, N. Y., assignor, by

mesne assignments, to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application November 15, 1945, Serial No. 628,942

y viding means for forcibly exhausting iiuid leakage which would otherwise collect within the casing and interfere with and obstruct free movement of parts moving within the casing.

A further object of the invention is to evacuate liquid leakage from within the casing of a rotary pump or motor and to utilize the space thus provided as an expansion chamber for the iluid employed in hydraulic circuits which are entirely air tight.

Another object of the invention is to provide an hydraulic pump or motor with an enclosed reservoir for the iluid employed in the device, which together ywith work output means, and suitable interconnecting conduit means, may provide an entirely enclosed hydraulic power circuit not subject to atmospheric pressure.

Another object of the invention is to provide an improved hydraulic pump or motor assembly which is compact, and the operation of which is not affected by changes in atmospheric pressure.

Other objects of the invention will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features o1" construction, combinations of elements, arrangements of parts, and in the several steps andrelation and 4order of each of said steps to one or more ofthe others thereof, all as will be pointed out in the following description, and the scope of the application of which will be indicated in the following claims.

The invention will best be understood if the following description is read in connection with the drawings, in which, l

' Figure 1 is a schematic view showing an enclosed propulsion iiuid reservoir and a work piece interconnected in an entirely enclosed circuit which is thus not subject to atmospheric pressure or changes thereof; Figure 2 is a verticalsectiofn of a device embodying my invention;

sartly cut awayto show the reservoir; y,

2o claims. (ci. 10344) Figure 5 is a perspective View on an enlarged scale of dish-like member 56; and

Figure 6 is -a vertical cross section through said member.

In Figure 1 an hydraulic rotary pump A, such as is shown in detail in Figures 2 4, is shown connected with a work output means such for example a-s W, by fluid conduit means which is entirely enclosed thus providing a complete hydraulic circuit which is not affected by atmospheric pressure, or by changes inatmospheric pressure due to any cause, Aas for example to change of altitude or change in weather, or both. Since windshield wiper mechanism is illustrated as the work output means W a cross over valve V is included in the circuit.

vThe device shown herein in Figures 2 4, and which may be utilized either as a pump or a motor depending upon the direction of flow of the uid employed, comprises a casing including a main body portion I0 and the combined cover and mounting standard or iiange Il, which may be secured to the body portion by the cap screws I2. i

Extending into the casing in alignment, from opposite sides, are the pintle I3 and the power shaft M. Mounted within the casing for rotation'on the pintle is the rotor I5, comprising a number of cylinders I6 in each of which is a piston l'l vthe outer end of which is adapted to abut against and is free to move on the inner race of a track ring assembly comprising the inner rotatable race I8 and the outer xed race i9, the races being separated by the steel balls 20;-

The track ring assembly is of less diameter than the interior of the casing and between the outer race I9 and the inner wall of the casing a spring member 2i (Figure 3) is interposed tending to urge the track ring into a position eccentric to the axis of the rotor. The position of the track ring-i5 further controlled by means ofthe support clips 22 and 23. rAs illustrated herein support clip '22 is held in place by the screw 24 extending through the casing wall, the inner g face of the screw being concave to provide a seat for the ball bearing 25 interposed between the screw 2d and the clip 22.- The clip 23 is retained in place by the screw 26 which is provided with an inwardly opening bore 21 in which is received the plunger 23 projecting outwardly` from clip 23. The position of plunger 28 withinbore 21 is determined by spring member 2S surrounding plunger 23 and having its extremities resting against the inner wall of the casing I0.

Extending through the casingwall intermediate the screws 24 and 25, and disposed in triangular arrangement with spring 2| and positioning clip 22, is a coarse stroke adjusting screw 30, and extending radially through screw 30 is an adjusting screw 3l adapted for making fine adjustments.

Power shaft I4 is interconnected with rotor I5 in any suitable way as by pins 35 interconnecting semi-cylindrical bores 35a provided in opposed relation in the circular flange 35 of the rotor and: in the flange 3l positioned on the inner endy of power shaft I4.

Pintle I3 is provided withfthe axially extending bores 40 and 4I adapted to communicate sucsively with the cylinders of the rotor assembly through the ports 4I]a and 4 Ia respectively, which are spaced apart angularly aroundthe `pintle and connected by the surface slot 42a. Interposed between the pintle I3 and the inner periphery o'fi the rotor I5 is the force fitted bushing 42 having the'ports 43a adapted to register-with the'` ports to the cylinders. Bore 4i) isenlarged' at its outer end, wliichis at the topl of the' device as shown, and this enlarged portion is provided with@ aA thread 44 to receive a fluid conduit connection. Theouter' end of bore 4I communicates through port 45with the fluid passage 45; which, lasshown', extends into the casing atright ang-les to the pintle I3, and communicatesthrough the-perf'rated'tubular wall member 4-'I' with a-reservoir 48" which itwill benotedis-entirely encl`osed=andthus-notsubj ect tolatmospheric-pressure;

having the inwardly projecting threaded shaft- 50 `adapted tir-engage in the-casing'bossl' extending upwardly in the reservoir.`

The partition means-47, which desirably-'may be of-w-ire mesh, serves to permit' a ready-flow offf propulsion iluidV from the reservoir into the conduit- 46 while preventing loss of energy due to.

turbulence and surging ofthefluid within` thev reservoir and between conduit 46' and the' reservoir. The outerv end of1ccnduit-46 may alsofbe enlarged if desired and provided with a thread 5-2 to-receive the end of a\ fluid condui'tc'onnection. o

Positioned-within the casing I E under the rbtb'r? assembly .a chamber or sump 5,4- isV provided.

adapted tocollect fluid leaking' from the rotor assembly and to confine it' in a closure from which it isA exhausted as will be described. As illustrated herein the= chamber. isi somewhat vlike'k a':

flattened bottle having a-cylindricalbody portiony ofsubstantial radius butnarrow axially, with an'y upwardly opening mouthformingV the port 53 which; is adapted t'o receive fluidi leaking frumpbw'er shaft M1, asby` pin 58, in shaft! I4 which pin'` engages slots; 58a inthe-central'hub `(i2-ofl member 56'. Thismember isdish-shaped having aiconcavity 60 in its upper surface, surroundinga: centralhub 62, to collect'lealkageiluid., and ex'- tending through the' peripheral rim" 53" of the member' radially extending ports 54 are provided through which-fluid is expelled under centrifugal force when .the member` is rotated,l thereby setting. up al rotary flow cif: the leakage; fluid; within Access to' reservoir 48 isv had through the screw cap 4d the chamber 54 around the periphery of member 56 and against the outer wall of the chamber.

In high pressure hydraulic pumps and motors generally leakage occurs, as for example between the pistons and the ycylinder bores, and between the pintle and the surrounding bushing, and unless means are provided for preventing it this leakage accumulates in the casing and' llls the space surrounding the rotor, and contact between the' leakage fluid in the casing `and the rotating rotor creates friction with resulting loss in efciency. In the embodiment of the invention disclosed herein leakage occurs between the pistons' and the cylinder bores I6 and also between bushing 42 and pintle I3. This leakage finds its way into the space below the rotor, and except for-'being exhausted as provided for herein would completely illl the casing and thus be in frictional contact' with the rotor.

Leakage iluid collecting in concavity 60 is confined therein, and' in chamber 54 afterY having been expelled from the concavity- 50 through ports 54, by thel annular baille 66. Baillie-56:y isby bent up at both its inner and outer peripheriesforming, an inner flange 58 which-forms the port 53,V and the outer flange lll which has an out--A wardly projecting lip I2 fastened as by screw I4- to the upwardlyprojecting flange 'I6 of the casing.

The chamber 541is designed tobe-eccentricwith respect-tothe axis-of rotatable member 55; which as illustrated herein is the axis of power shaft |45; inorder that the space'surrounding' theperiph-` ery of member 56 will be non-uniform radiallyL Thus' in thespaee around the periphery of member' 56 a pressure will be built up, when member 56= rotates; which will. be greatest at the greatestl radial distance from theaxisof rotation of'mem ber-56;V

Interconnecting the low pressure sidelof thelpump or motor. and the interior of the said chamber 54. is a fluid passage 18, preferably'having its. mouth located` at the greatest radial distance` from the axis of. rotation of the said membe;1 56,. whereby?, due to the,l pressurezbuilt up, within the' y chamberwhen.member'is rotatedgsth'eleakagel fluid is expelled from chamber 54A thrcugnthef said-passage 'lSand isV returned to. the low'pressure'side of thepump or motor. It will now-be'- understood that member 58 serves as. a scavenger. pump operating. in a continuously evacuated: pumping chamber, and cooperating withxiluid passage 1,8 to return leakage fluid from the ;in= teror of the casing, to the low'pressureV side of the 'pump orv motor, with the result that the: infterior of the casing, and particularly the space'4 aroundthe rotor is kept free of leakage. fluid;

It will be noted that during filling of the reser voir with fluid via the bore 55 any fluid which can pass through passage T3 will not completely; or even substantially fill the expansion chamber 54 sinceV it. is filled with air and would merely build up a slight pressure therein. During rota tion of the pump the member 56 will tend to.' expel fluid into the reservoir 4Bl andcontinueits scavenging :action whenever the expansion cham-v ber fluid leakage level is above the lip ofthe, wall 68. However, during the scavenging operation air inthe expansion chamber 54 will. mii:` with a certain amount of the leakage oil as the oil is agitated around thel rotor and'will be' carried out of said chamber into the reservoir where' the-air tends to rise from the liquid oil to pressurize the reservoir. In a closed system such asY this apressure balance is set upA at a normal operating temperature, i; e., th'e airpressure in the expansion chamber will assume a certain pressure value commensurate with said temperan ture and the evacuation pressure capacity of the pumping element 55 as compared to the pressure in reservoir 43. Hence the normal rise in pressure `due to temperature in reservoir i8 will be enhanced by the pumping action of the scavenger element 56 which as mentioned above will at times be pumping an air-oil mixture. Therefore, with a closed system as described, the pump ing mechanism, for given power conditions, will operate at a given pressure regardless of outside pressure variations such as changes in altitude in an aircraft.

To facilitate ow of leakage iluid into the concavity 65 in member 5S the power shaft lli may be made with a hollow bore 89 leading from its inner extremity just below the inner end of the pintle and communicating with concavity 6! through the lateral ports 8E in the annular wall of shaft i4 and the ports 62a in hub 62. Perforations -84 may also be provided through the charge passage, said housing deiining la reser voir therein communicating with said inlet passage, said housing defining a sump below said elements, a liquid return passage interconnecting said sump and said reservoir, and additional pumping elements in said housing for transferring liquid' from said sump to said liquid return passage.

baille 56 to permit leakage fluid which has not ,relation to the track ring assembly.

Any vsuitablesealing means may be provided surrounding the power shaft E4. As illustrated herein this means includes a loose washer 3B, the forceiitted washer 90 and the packing assem bly 92.

By Vexhausting leakage fluid from within the casing'not only is the efficiency of the device increased by eliminating the Waste energy expended in friction between the rotor and leakage iluid in the space through which the rotor turns, rbut a morey compact system is made possible in which all parts of the iiuid circuit are air-sealed and the space within the casing isv employed as an expansion chamber for the fluid. Thus the nuid within the sealed system may be exchanged in either direction through the fluid passage interconnecting the reservoir and the sump, and the space ywithin the casing, which is kept substantially evacuated as has been described, will function as an air chamber to apply air pressure to the liquid in said reservoir and thereby increase its pressure head above that due to the liquid in said vreservoir and maintain said pressure head irrespective of external atmospheric pressure.

It will thus be seen that there has been provided by this invention a method and apparatus, in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of-the invention, it is tobe understood that all matter hereinbeiore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

What I claim is:

1. A power translating device comprising, in combination, a housing having liquid inlet and discharge passages therein, liquid displacement power conversion elements in said housing for transferring liquid from said inlet to said dis- 2. A power translating device comprising, in combination, a housing `having liquid inlet and discharge passages` therein, liquid displacement power conversion elements in said housing for transferring liquid from said inlet to said discharge passage, said housing defining a reservoir therein communicating with said inlet passage, said housing defining a sump below said elements, a liquid return passage interconnecting said sump and said reservoir, pumping elements in said housing for transferring liquid from said sump to said liquid return passage, and a common drive shaft extending into said housing and driving said liquid displacement power conversion elements and said pumping elements.

3. A power translating device comprising, in combination, a housing having liquid inlet and discharge passages therein, liquid displacement power conversion elements in said housing for transferring liquid from said inlet to said discharge passage, said housing defining a reservoir therein communicating with said inlet passage, said housing defining a sump below said elements, a liquid return passage interconnecting said sump and said reservoir, a centrifugal pumping element in said sump, said sump and said pumping element being circular and said pumping element being positioned eccentrically with respect to the axis of said sump, said liquid passage having a port located in the portion of the periphery of the sump which is at the greatest radial distance from the axis of said pumping element.

4. A power translating device comprising, in combination, a casing having a first chamber therein, a rotor in said chamber having a plurality of substantially radial cylinders therein and pistons projecting from the outer ends oik said cylinders, a drive shaft extending into said casing and coupled to said rotor, bearings carn rying said rotor, a rotating guide member in controlling engagement with the outer end of said pistons for determining the positions of said pistons in said cylinders, bearings for said guide member, the axis of rotation of said guide mem-- ber being parallel to the axis oi rotation oi said rotor, said casing having liquid inlet and outlet passages communicating with said cylinders, and a liquid reservoir chamber communicating with saidinlet passage, said casing also having .a second chamber in the lower portion thereof, a liquid passage extending from the peripheral portion of said second chamber to said reservoir through which liquid may be exchanged between said reservoir and said second chamber, and a centrifugalpumping element mounted for rotation in said second chamber by which liquid in said second chamber may be transferred to said reservoir.

5. A power translating device comprising, in combination, a casing having a iirst chamber therein, a rotor in said chamber having a plu rality of substantially radial cylinders therein' and pistons projecting from the outer ends of said cylinders, a drive shaft extending into said casing and coupled to said rotor, bearings carrying said rotor, a rotating guide member in congamers? 7,* trolling engagement with: the. outerV end` of" said pistons`= for determining the'. positions; of said pistonsinisaid cylinders,. bearings for saidV guide member.,1tna axis ofrctation'ofsaid guide member.' beingparallelto the axis of rotation of Vsaid rotor, said casing. also having liquidV inlet. andr outlet.passages'V communicating with said cylinders and a liquid reservoir chamber communieating.y with said inlet passage, said casing. also having. ase'cond chamber in the lower portion thereof, aliquid return passage. extending. from` the peripheral portion of said second` chamber to said reservoir, and a' centrifugal pumping element in said second chamber, said pumping element being disposed in the bottom of said seoond chamber and comprising a dish-like rotor having, aV bottom and a rim carrying radiating liquid passages therein, and means for connecting said pumping element to a source of power.

6. A power translating device comprising, in combination, a casing having a first chamber therein, a rotor in said chamber having a plurality of substantially radial cylinders therein and pistons projecting from the outer ends of said cylinders, a drive shaft extending into said casing and coupled to said rotor, bearings carrying said rotor, a rotating guide member in controlling engagement with the outer end of said pistons for determining the positions of saidpistons in said cylinders, bearings. for said guide member, said casing also having liquid inlet and outlet passages communicatingY with. said cylinders and a liquid reservoir chamber cornmunicating with said inlet passage, said casing also having a second chamber in the lower portion thereof, a liquid passage extending from the peripheral portion of said second chamber to said reservoir, and a centrifugal pumping element disposed in the bottom of said second chamber and comprising. a dish-like rotor haying a bottom wall and a rim carrying radiating liquid passages therein, said second chamber and pumpingelement being substantially circular and said pumping element being positioned eccentrically with respect to the axis of said second chamber, the. entrance of said liquid return passagebeing located in the portion of the periphery ofthe second chamber which is at the greatest radial distance from the axis of said pumping element.

7. A power translating device comprising, in combination, a casing having a first chamber therein, a rotor in said chamber having a plurality of substantially radial cylinders therein and.: pistons projecting` from the outer ends of saidcylinders, a drive shaft extending into said casing and coupled to said rotor, bearings carrying said rotor, a rotating guide member in controlling engagement with the outer end of said pistonsfor.. determining the positions ofA said pistons in said. cylinders, bearings for said guide member, said casing also having, liquid inlet and out-let passages communicatingI with said cylinders anda liquid reservoir chamber communicating. with said inlet passage, said casing` also having. a second chamber in the lower portion thereof surrounding the axis of said shaft, a liquid return passage extending from the peripheral portion of` said second chamber to said reservoirand a centrifugal pumping element rotatable about the axis of said shaft and" coupled' to said shaft for rotation thereby, said pumping element being disposed in the bottom of said second chamber, and said pumping element comprising av dish-likefrotor having a bottom wall andy a rim' carrying radiating' liquid'- passages" 8'.. therein and leakage liquid guide walls. in said casing for conveying leakage liquid into said dishlike rotor.

8. A power translating device comprising, in. combination, a casing having a first chamberr therein, a pintle extending downwardly into said chamber and having liquid inlet and outlet passages'therein and terminating in ports on oppo-'v4 site sides of said/pintle, a rotor in said chamber: having a` plurality of substantially radial cylinders therein and pistons projecting from 'they outer' ends of said cylinders, said pintle comprising a bearing upon which said rotor is mounted for rotation about a vertical axis with theinner ends of said cylinders passing over said ports during rotation of said rotor, a rotating guidey ring in controlling engagement with the outer ends of said pistons for moving said pistons inwardly in said cylinders during a portion of their rotational cycle, bearings pivoting said guide ring for rotation about an axis parallel to said axis of rotation of said rotor, a vertical drive shaft extending into said casing from the bottom thereof along the axis of said rotor, said shaft beingv coupled to said rotor, and a liquid reservoir cham.- ber in said casing communicating with said inlet passage and located at a higher position. in said casing than said ports.

3.v A power translating device comprising, in. combination, av casing having a first chamber therein, a pintle extending'downwardly into said. chamber and havingy liquid inlet and outletpassages therein and terminating in ports on oppo- .site sides of said pintle, a rotor in said chamber having a plurality of substantially radial cyln.- ders therein andv pistons projecting from the.4 outer ends of said cylinders, said pintle comprising a bearing upon which said rotor isl mounted for rotation about a vertical axis with. the inner ends of said cylinders passing over said-portsduring rotation of said rotor, a rotating guide ring in controlling. engagement with the outer ends of said pistons for moving said. pistons inwardly in said. cylinders during.. a portion of their rotational cycle, bearings pivoting,

said guidev ring for rotation about an axis parallel and eccentric to said axis of rotation.` of said` rotor, alvertical drive shaft extending into said casing from the bottom thereof along then axis of said rotor, said shaft being coupled to said rotor, and a liquid reservoir chamber in saidv casing communicating with said inlet passage and located at a higher position in said casing" than said ports, said casing also having a second chamber in the lower portion thereof surround-v ing the axis of said shaft, a liquid return passage extending from the peripheral portion of said second chamber to said reservoir, and a cen-- trifiigal-l pumping element rotatable about the axis of said shaft and coupled to said shaft for rotation thereby, said pumping element being disposed in said second chamber;

10'. A power translating device comprising, in" combination, a casing having a first chamber therein, a pintle extending downwardly into said chamber and having liquid inletl and outletV pas'- sages therein and terminating in ports on opposite sides of said pintle, a rotor in said cham'- ber having a plurality of' substantially radial" cylinders therein and pistons projecting from the outer ends of'said cylinders", said pintle' comprising'a be'aringupon` which saidl rotor is mounted for rotation about a' vertical axis with the inner ends of said cylinders passing-.over said' ports duringrotationof said rotor, a rotating guide ring in controlling engagement with the outer ends of said pistons for moving said pistons inwardly in said cylinders during a portion of their rotational cycle, bearings pivoting said guide ring for rotation about an axis paralleland eccentric to said axis of rotation of said rotor, a vertical drive shaft extending into said casing from the bottom thereof along the axis of said rotor, said shaft being coupled to said rotor, and a liquid reservoir chamber in said casing communicating with` said inlet passage and located at a higher' position in said casing than said ports, said casing also having a second chamber in the lower portion thereof surrounding the axis of said shaft, a liquid return passage extending from the peripheral portion of said second chamber to said reservoir, and a centrifugal pumping element rotatable about the axis of said shaft and coupled to said shaft for rotation thereby, said pumping element being disposed in the bottom of said second chamberv and said pumping element comprisingra dish-like rotor having a bottom wall and a rim carrying radiating liquid passages therein.

, 11, A power translating device comprising, in combination, a casing having a rst chamber therein, a pintle extending downwardly into said chamber and having liquid inlet and outlet passages therein and terminating in ports on opposite sides of said pintle, a rotor in said chamber having a plurality of substantially radial cylinders therein and pistons projecting from the outer ends of said cylinders, said pintle comprising a bearing upon which said rotor is mounted for rotation about a vertical axis with the inner ends of said cylinders passing over said ports during rotation of said rotor, a rotating guide ring in controlling engagement with the outer ends of said pistons for moving said pistons inwardly in said cylinders during L a portion of their rotational cycle, bearings pivoting said guide ring for rotation about' an axis parallel and eccentric to said axis of rotation of said rotor, a vertical drive shaft extendinginto said casing from the bottom thereof along the 'axis of said rotor, said shaft being coupled to said rotor, and a liquid reservoir chamber in said casing communicating with said inlet passage and located at a higher position in said casing than said ports, said casing also having a second chamber in the lower portion thereof surrounding the axis f said shaft, a liquid return passage extending from the peripheral portion Vof said second chamber to said reservoir, and a centrifugal pumping element rotatable about the axis of said shaft and coupled to said shaft for rotation thereby, said pumping element being disposed in said second chamber and said pumping element comprising a dish-like rotor having a bottom wall and a rim carrying radiating liquid passages therein, and leakage liquid guide walls in said casing for conveying leakage liquid into said dish-like rotor.

12, In an hydraulic power translating device comprising, a casing, a pintle extending into said casing and having liquid inlet and discharge passages therein terminating in ports on the opposite sides of said pintle, a rotor having a plurality of radial cylinders therein and pistons projecting from the outer end of said cylinders, said pintle comprising a bea-ring upon which said rotor is mounted for rotation around the pintle with the inner ends of said cylinders passing over said ports during rotation of said rotor, a track ring rotatably `mounted intermediate the pintle and the casing in controlling engagement with the outer ends of said pistons for moving said pistons inwardly in said cylinders respectively during a portion of their vrotational cycle, and means for -controlling the'position of the axis of rotation of the track ring with respect to the axis-v of rotation of the rotor comprising, a ball contact and means supportingit within the casing in position to engage the exterior of said trackv ring, an adjustable positioning screw extending through the casing and adapted to contact the exterior of said track ring, and resilient means supported in the casing and pressing kagainst the exterior of the track Vring and'urging it against the said ball contact and said positioning screw."

r13. A liquid-mechanical power converter comprising, in combination, a casing having a chami Y ber therein and. liquid inlet and outlet passages entering said chamber, hydraulic-mechanical power conversion members for transferring liquid from said inlet to said outlet passage, a power transmitting shaft coupled to said power conversion members and extending through said casing wall', a reservoir communicating with one of said passages, liquid conduits connecting said outlet and inlet 'passages outside said converter, a liquid passage interconnecting said reservoir and the lower part of said chamber which is thus able to serve as an expansion chamber for the liquid of the system and to apply air pressure to the liquid in said reservoir and thereby increase its pressure head above that due to the liquid in said reservoir and maintain said pressure head irrespective of external atmospheric pressure, and means for exhausting liquid from the lower part of said chamber and for returning it through said liquid passage to said reservoir.

14. A radial pump comprising, in'combination, a casing having a chamber therein,- a pintle extending into said chamber and having liquid inlet and outlet passages therein and terminating in ports on opposite sides of said pintle, a rotor in said chamber mounted to lrotate on said pintle, said rotor having a plurality of radial cylinders therein and pistonsprojecting from the outer ends of said cylinders, the inner ends of said cylinders being positioned to pass over said ports during rotation of said rotor, a rotating guide member in controlling engagement with the outer ends of said pistons for moving said pistons inwardly in said cylinders during a portion of their rotational cycle, bearings pivoting said guide member for rotation on an axis parallel to but offset from the axis of rotation of said rotor, a drive shaft extending through the wall of said casing and coupled to said rotor, a liquid reservoir cornmunicatng with said inlet passage, liquid conduits connecting said liquid outlet and inlet passages outside said pump, said casing and said conduits and reservoir together defining a sealed system, said casing having a liquid return passage extending from the lower part of said chamber to said reservoir, and a liquid pump in the lower part of said chamber operatively positioned with respect to said liquid return passage for returning leakage liquid from said chamber to said reservoir.

l5. A power translating device comprising in Combination, a housing, a plurality of liquid passages extending through tlie Wall of the housing, liquid displacement power conversion elements movably mounted in said housing for transferring liquid from one of said passages to the other,

said housing defining a reservoir, a port extend- .ing Vthrough the housing wall into communicaition with said reservoir, and a removable plug accessible from outside said housing and adapted to be seatedin'and'to close said port, said reservoir being in communication with one of said 'liquid passages.

16. A power translating device comprising in combination, a housing having liquid inlet and discharge passages'therein, said housing defining a chamber having liquid displacement power conversion elements movably mounted therein for transferring liquid from -said inlet to said dischargepassage, a reservoir, in communication with oneof said liquid passages, and a liquid conduit separate fromsaid one passage interconnecting said reservoir and the interior of said chainber, and movable pumping elements in said chamber :adapted to transfer liquid from said chamber to said reservoir through said liquid conduit.

17. `A power translating device comprising in combination, a housing having liquid inlet and discharge passages therein, liquid displacement power conversion elements movably mounted in vsaid housing for transferring liquid from said ends of said cylinders, said casinghaving liquid i inlet and outlet passages communicating with said cylinders, a drive shaft extending into said casing and coupled to said rotor, bearings carrying said rotor, a rotating guide member in controlling engagement with the outer end of said pistons for determining the position of said pistons in said cylinders, a liquid reservoir communicating with said .inlet passage, a scavenger pumping means having its inlet in communication with liquid collecting in said casing, a liquid i passage extending from adjacent thebottom of the casing to said `reservoir by which liquid accumulating within the casing may be transferred to said reservoir, and means connecting said scavenger pumping means to a source of power.

19. A power translating device comprising in combination a casing, arotor in said casing having a plurality of substantially radial cylinders therein and pistons projecting from the outer ends of said cylinders, said casing having liquid inlet and outlet passages communicating with said cylinders, a drive shaft extending into said casing'and coupleditosaid rotor, bearings carrying said rotor, ya rotating guide member in ,con-

.trolling engagement with the ,outer end of .said pistons fordetermining the position of -said pistons in said cylinders, a liquid reservoir .communicating with said inlet passage, a chamber located below said sump and a passage communieating between said sump and said chamber, a centrifugal pumping element rotatably mounted lin. said chamber, means for interconnectingsaid pumping element to a source of power, and a liquid passageextending from'the peripheral portion of said pumping chamber to said reservoir through which liquid may be exchanged between `-said reservoir and said pumping chamber.

20. A power translating device comprising vin combination a casing, a rotor in said casing havfing -a plurality of substantially -radial cylinders therein and pistons projecting `from the outer ends of said cylindersliquid inlet and Outlet-passages communicating vwith said cylinders through -said ycasing, a drive shaft extending vinto said :casingfand coupled to saidzrotor, bearings -.carrying said rotor, a rotating guide rmember in controlling engagement .with the outer .end of -said ,pistons fordeterinining Lthe position-.of said pistons 4in said cylinders, a liquid reservoir communicating with said-inlet passage, a liquid passage extending .from the interior of said casing below said rotor to said reservoir, and means for exhausting liquid from-said casing to said reservoir through .said liquid passage, said liquid passage being adapted also to transfer liquid from the reservoir tothe interior of the casing to utilize said space as an expansion chamber for said reservoir.

ROGER HORTON.

.REFERENCES CITED The following .references are of :record in the leof this patent:

UNITED STATES PATENTS Number Name Date 762,055 Hibbard June 7, 1904 1,119,972 YMachlet Dec. 8, 1914 1,696,139 Ferris Dec. 18, 1928 1,821,772 Ruthman Sept. 1, 1931 1,961,592 Muller June, 1934 1,974,134 Douglas Sept. 18, 1934 1,978,441 Svenson Oct.,30, 1934 1,988,875 Sabario .Jan. 22, 1935 2,024,420 Benedek Dec. 17, 1935 2,115,121 .Philips Apr. 26, 1938 2,130,299 Ernst Sept. 13, 1938 y 2,208,041 Norin July 16, 1940 2,293,693 Wylie Aug. 18, 1942 2,303,627 Fuller Dec. 1, 1942 'FOREGN PATENTS Number Country Date 629,102 France July 18, 1927 

